MiR-155 Knockdown Protects against Cerebral Ischemia and Reperfusion Injury by Targeting MafB

Li Zhang,Chao Huang,Junfang Teng,Xiaohui Xu,Chao Liu

doi:10.1155/2020/6458204

Abstract

Background Studies have elucidated that the variable expression levels of miRNAs influence the inflammatory process in ischemic stroke. Nevertheless, the impact and potential mechanism of miR-155 in cerebral ischemia-reperfusion injury (CIRI) keep to be incompletely known. Methods The levels of miR-155 and MafB were determined via qRT-PCR, western blot, or immunohistochemistry assays in plasma of patients with CIRI, oxygen glucose deprivation/reoxygenation (OGD/R) induced SH-SY5Y cells, and mouse models with middle cerebral artery occlusion (MCAO). The association between miR-155 and MafB was validated via dual-luciferase reporter and western blot assays. Cell viability, apoptosis, invasion, and migration were evaluated through MTT, flow cytometry, Transwell and wound healing assays. Infarction volume was measured in MCAO mouse brain tissues by TTC assay. The expression of inflammatory mediators was measured by ELISA in cells and brain tissues. Results miR-155 level was upregulated whereas MafB was downregulated in the plasma of patients with CIRI, OGD/R-induced SH-SY5Y cells, also as mouse models with MCAO injury. Mechanistically, miR-155 directly targeted 3'UTR of MafB and restrained MafB expression in OGD/R injury SH-SY5Y cells. Downregulation of miR-155 attenuated OGD/R-induced injury through increasing proliferation, inhibiting apoptosis, enhancing invasion and migration abilities, and constraining the expression of inflammatory mediators (IL-1β, IL-6, and TNF-α) and inflammatory enzymes (iNOS and COX-2) in SH-SY5Y cells following OGD/R, while MafB inhibition reversed the protective effects. In vivo, downregulating miR-155 reduced the infarction volume in the MACO mouse brain. Furthermore, miR-155 knockdown inhibited the IL-1β, IL-6, and TNF-α) and inflammatory enzymes (iNOS and COX-2) in SH-SY5Y cells following OGD/R, while MafB inhibition reversed the protective effects. Conclusion Our results suggest that miR-155 knockdown alleviated ischemia-reperfusion injury by targeting MafB to improve the neurological function and inhibit inflammation response, highlighting a novel therapeutic strategist for CIRI.

Highlights

Ischemic cerebral stroke is an acute disease threatening human health, which is caused by the local brain blood supply obstacles and is influenced by multiple pathophysiological process factors, with the characteristics of high morbidity and high fatality [1]
Blood specimen (5 ml) was gathered into ethylenediaminetetraacetic acid (EDTA) tubes and centrifuged at 2000 ×g for 15 min at 4°C. en the upper layer plasma was used to detect the miR-155 and MafB levels of patients with cerebral ischemia-reperfusion injury (CIRI) and healthy subjects via qRTPCR. e collection of human plasma samples for research purposes was allowed by the Institutional Review Board and the Ethics Committee of the First Affiliated Hospital of Zhengzhou University, and each participant or their legal representatives subscribed to the informed consent form for the research
The qRT-PCR results demonstrated that MafB level was dramatically decreased following oxygen glucose deprivation/reoxygenation (OGD/R) injury in comparison to the control (Figure 2(b)). e results above revealed that miR-155 and MafB played a crucial role in SH-SY5Y cells with OGD/R injury

Summary

Introduction

Ischemic cerebral stroke is an acute disease threatening human health, which is caused by the local brain blood supply obstacles and is influenced by multiple pathophysiological process factors, with the characteristics of high morbidity and high fatality [1]. E levels of miR-155 and MafB were determined via qRT-PCR, western blot, or immunohistochemistry assays in plasma of patients with CIRI, oxygen glucose deprivation/reoxygenation (OGD/R) induced SH-SY5Y cells, and mouse models with middle cerebral artery occlusion (MCAO). MiR155 level was upregulated whereas MafB was downregulated in the plasma of patients with CIRI, OGD/R-induced SH-SY5Y cells, as mouse models with MCAO injury. Downregulation of miR-155 attenuated OGD/R-induced injury through increasing proliferation, inhibiting apoptosis, enhancing invasion and migration abilities, and constraining the expression of inflammatory mediators (IL-1β, IL-6, and TNF-α) and inflammatory enzymes (iNOS and COX-2) in SH-SY5Y cells following OGD/R, while MafB inhibition reversed the protective effects. Our results suggest that miR-155 knockdown alleviated ischemia-reperfusion injury by targeting MafB to improve the neurological function and inhibit inflammation response, highlighting a novel therapeutic strategist for CIRI

Methods

Results

Conclusion